The invention concerns a method of kneading dough for making bread or similar products and a device for implementing the said method.
The document EP-A-0 246 768 describes a method and apparatus for kneading bread dough in an oxygen-enriched atmosphere. To this end, oxygen or oxygen-enriched air is introduced into the chamber of the apparatus contained in the dough before or during kneading. The atmosphere in the chamber is then discharged through a discharge pipe. This addition of oxygen promotes the action of the ascorbic acid, used as a single improving product (known as an improver in the technical field).
This document describes that the application of a partial vacuum in the chamber is not necessary but that it can be implemented before the introduction of the oxygen or the oxygen-enriched air.
However, this method does not make it possible to control the development of the bubble structure in the bread dough.
According to the document EP-A-0 629 115, it is known that the production of a partial vacuum during kneading improves the uniformity of the structure of the soft part of the bread. However, the creation of a partial vacuum removes the air, which reduces the oxidation of the improvers used by bakers (ascorbic acid or potassium bromate) for intensifying the formation of the gluten lattice and, stabilising the structure of the bubbles.
The document EP-A-0 629 115 describes a dough kneading method for optimising the use of ascorbic acid as an improver. To this end, the method comprises the kneading of the dough ingredients in the presence of air or a gas containing oxygen. During a first phase of this kneading, an overpressure is applied to the atmosphere surrounding the dough, whilst a reduced pressure is applied during a second phase of the kneading. The first phase allows oxidation of the ascorbic acid, the second phase controlling the structure of the bubbles in the dough.
This method has the drawback of requiring two kneading phases, including one phase under air overpressure which is difficult to achieve with normal kneading means.
This is because high forces are exerted by the air pressure on the mixing chamber and on its mechanical environment such as for example the mixing tool or tools, the sealing joint or joints, and the lid of the vessel.